I am convinced that the absolute most critical aspects of AC line noise and surge issues can be addressed with the most simple AC noise filters and MOV solutions. Based on decades of experience, science, and advice from other experts, the most one will ever NEED from an AC conditioner is found in all of the Tripplite IsoBar products. They offer very effective noise filtering, isolation, and absolute surge protection in very affordable solutions.
The only reason to spend more is if you experience regular brown-out conditions in your house. If you do, then a true AC regulator is the only practical solution, and those can get very expensive.
There is absolutely no value in adding meters, lights, or other gimmicks to the AC solution, and I find it silly that people will spend so much on solutions.
There are extreme solutions, such as the Furman balanced power products for pro-recording studios, which can offer the ultimate in noise elimination, but if you aren't already spending tens of thousands of dollars on speakers and room acoustic treatments, then the benefits of balanced power is pointless.